In a combustor having a combustion chamber liner arrangement comprising floatwall panels, the combustor comprises an outer shell, which is lined on the inside with heat shields, referred to herein as floatwall panels. One example of such an arrangement is disclosed in U.S. Pat. No. 4,302,941. Each floatwall panel is attached to the outer shell with studs and nuts. The middle stud and the corresponding hole on the shells are made to tight tolerance to locate the floatwall. The rest of the studs and holes are loosely made to allow freedom of movement.
In certain arrangements, there are dilution holes near the trailing edge of the floatwall panel, which communicate with corresponding dilution holes in the outer shell and allows cooling air to dilute the hot gas. In addition to dilution holes, the outer shell also has smaller air impingement holes to allow cooling air to enter between the floatwall panel and the outer shell, in order to cool the back of the floatwall panel. This cooling air exits the effusion holes on the surface of the floatwall panel and forms a film on the surface of the floatwall panel.
Establishing and maintaining a film of cooling air along the inside surface of the floatwall panel helps to form a barrier against thermal damage to the floatwall panel. Challenges in the floatwall arrangement include the need to purge hot gas from between the floatwall panel and the outer shell, and the need to maintain the film of cooling air beyond the trailing edge of the floatwall panel to cool the region behind the dilution holes.
Features that distinguish the present invention from the background art will be apparent from review of the disclosure, drawings and description presented below.